Correct 笔套 / bǐtào / Strokes Definition the cap of a pen, pencil or writing brush/the sheath of a pen (made of cloth, silk or thread) Example As a Noun pen sheath［made of cloth or silk］ 笔套 - Chinese Dictionary Definition the cap of a pen, pencil or writing brush/the sheath of a pen (made of cloth, silk or thread) the cap of a pen, pencil or writing brush/the sheath of a pen (made of cloth, silk or thread)